docs: def _get_mean(self, sites, rup, dists, imt, stddev_types):
          """
          See :meth:`superclass method
          <.base.GroundShakingIntensityModel.get_mean_and_stddevs>`
          for spec of input and result values.
          """
          # Zhao et al. 2006 - Vs30 + Rrup
          mean_zh06, stds1 = super().get_mean_and_stddevs(sites, rup, dists, imt,
                                                          stddev_types)
          #
          # Atkinson and Macias (2009) - Rrup
          gmpe = AtkinsonMacias2009()
          mean_am09, stds2 = gmpe.get_mean_and_stddevs(sites, rup, dists, imt,
                                                       stddev_types)
          #
          # Abrahamson et al. (2015) - Rrup + vs30 + backarc
          gmpe = AbrahamsonEtAl2015SInter()
          mean_ab15, stds3 = gmpe.get_mean_and_stddevs(sites, rup, dists, imt,
                                                       stddev_types)
          #
          # Ghofrani and Atkinson (2014) - Rrup + vs30
          gmpe = GhofraniAtkinson2014()
          mean_ga14, stds4 = gmpe.get_mean_and_stddevs(sites, rup, dists, imt,
                                                       stddev_types)
          # Computing adjusted mean and stds
          cff = self.SITE_COEFFS[imt]
          mean_adj = (np.log(np.exp(mean_zh06)*cff['mf'])*0.1 +
                      mean_am09*0.5 + mean_ab15*0.2 +
                      np.log(np.exp(mean_ga14)*cff['mf'])*0.2)
          return mean_adj